PHILADELPHIA — In a year of high payrolls missing the postseason and 100-win teams flaming out early, the stars on the Phillies proved free agency still works.

Led by Bryce Harper, Trea Turner and Game 4 hero Nick Castellanos, the Phillies vanquished the Atlanta Braves in their division series matchup for the second consecutive season.

Castellanos, who signed a five-year, $100 million contract before the 2022 season, hit two home runs in Thursday’s 3-1 clinching win, one day after doing the same in Game 3. He is the first player in postseason history with back-to-back multihomer games.

“When we were 16, 17 years old, playing for Team USA, he did the same stuff,” a bare-chested, champagne-soaked Harper said after the win. “In the biggest tournaments, on the biggest stage, that’s Nick Castellanos. And that’s why he’s here.”

Castellanos signed with the Phillies a day after Kyle Schwarber signed for $79 million. One year later, it was Turner’s turn. He inked a $300 million deal last winter — $30 million less than what Harper signed for in 2019. The money has been well spent. Harper hit two home runs in Game 3 while Turner added one in both Games 3 and 4.

“[President of baseball operations] Dave Dombrowski has been around the block a lot,” owner John Middleton said during the celebration. “He understands that. You have to trust Dave. He knows the character of the guy you’re signing.”

Dombrowski added: “I have always felt like every good club has to have a core of veteran players and a group of young players coming up. It starts [with] Bryce, but we added to that mix.”

The free agents fueled the series win over the Braves, but it was one of the young players who might have saved Game 4. With the bases loaded and two outs in the seventh, Ronald Acuna Jr. hit a ball to center field that Phillies rookie Johan Rojas tracked and caught as he leapt against the wall. It ignited the sold-out crowd at Citizens Bank Park — one of the more hostile environments in the game.

“This is the most unbelievable home-field advantage in baseball right now,” Dombrowski said. “I’ve never really seen anything like this.”

The Phillies steamrolled the Braves in Games 3 and 4 — first by taking it to young starter Bryce Elder on Wednesday then following it with three home runs against ace Spencer Strider in the clincher. Philadelphia gave Atlanta a taste of its own medicine, outhomering the Braves 11-3 in the series, including nine in the two home games, tying a postseason record for home runs in back-to-back games. The Braves led MLB in long balls during the regular season but came up short in this series.

“Well, to start with, Trea and Harp and Nick, I mean I can’t tell you how big they are on our club right now,” manager Rob Thomson said. “I don’t think the moment gets them at all. In fact, the moment, I think, helps Harp a little bit. But Trea has been unbelievable. That home run he hit today was huge. Nick’s two home runs were huge. Harp’s two home runs yesterday were huge. Those guys just — they step up.”

Meanwhile, the Braves, who topped the majors with 104 wins in the regular season, are left with unanswered questions. Like, why have they dominated the regular season but can’t get it done against their division rival in the postseason?

“That’s a good question,” Braves manager Brian Snitker said. “I wish I had the secret sauce for that. I feel like last year all of a sudden, they got everybody healthy. And they got big-time players on this team. Yeah, I don’t know. I really don’t know.”

The Braves might also be left wondering how their midseries controversy impacted the outcome. Shortstop Orlando Arcia had to answer questions after yelling “atta-boy Harper” in the Braves’ clubhouse after Game 2’s ending, when the Phillies star got doubled off at first base. Harper’s stare down of Arcia after hitting two home runs Wednesday immediately went viral, prompting Arcia to tell reporters Harper “wasn’t supposed to hear it.”

That quote ended up on the back of a T-shirt worn by one Phillies player during the celebration after Game 4.

“It’s fun,” second baseman Bryson Stott said. “I don’t know what it did for us, but the crowd loved it.”

The crowd also loved the record-breaking homers from Castellanos. He was featured on the scoreboard after his second one Thursday, soaking in the limelight usually held for Harper or others.

“Whenever you have 46,000 people cheering you on and trying to get the other team out of their comfort zone, that’s a huge advantage,” Castellanos said.

The environment will make for an interesting National League Championship Series as the Phillies will host a young Arizona Diamondbacks team in Game 1 on Monday. Led by their powerful veterans, the Phillies are one step away from returning to the World Series for the second consecutive season. This time, they aim to finish the deal.

“Eight more to go,” Dombrowski said. “It really starts with our stars.”